[Talk-at] kittsee - semiautomated import of buildings from basemap.at

[Jozef Riha]

Thank you all for sharing your views. I chose not to go further with the
import - instead I will describe the procedure I used  - maybe someone
could come up with improvements that would make the result look
better/actually usable.

- create a basemap.at xml config for mobac (http://mobac.sourceforge.net/),
select and export to png file (zoom: 19)
- open png file in gimp, select -> by color, click on one building,
copy&paste to new file, threshold, index -> 2 colours (potrace requires
bi-color image), save buildings into pnm file
- potrace -t 100 -k 0.3 -o kittsee.svg -s kittsee.pnm
- import to josm (importvec plugin, 10 000 units = 1995 m)
- select all ways (^f - type:way - simplify using simplifyarea plugin,
using too aggressive values could result in triangular buildings, OTOH too
forgiving ones could leave you with too many nodes and/or speckles caused
by nearby housenumbers or jpeg artefacts
- turn on basemap.at tms background and align, tidy up, add tags

All the best,

jose

On Thu, Dec 26, 2013 at 5:09 PM, Frederik Ramm <frederik at remote.org> wrote:

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>
> Hi,
>
>     before this is imported it would at least need proper
> documentation on the Wiki import catalogue.
>
> In addition to the points mentioned by Michael -
>
> > * adjacent buildings do not share nodes * no multipolygons at
> > buildings with holes - those would have to be created manually *
> > The buildings are not orthogonalized (q in JOSM) * nodes at very
> > obtuse angles (e.g. 88°) should be removed.
>
> I would like to add
>
> * source tag on every building (source tag on changeset would be enough)
> * existing buildings are not reflected - they would have to be removed
> from the import data.
> * very small buildings seem to be badly traced (triangular shapes etc)
> - - perhaps just drop everything below 10 square metres or so.
>
> There seem to be a number of mismatches between the data and Bing
> imagery - but I guess that's because basemap.at is newer? Examples:
> http://www.remote.org/frederik/tmp/kittsee.png
>
> Bye
> Frederik
>
> - --
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"
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